In the field of telecommunication, it is often necessary to update a number of remote (slave) data bases according to a master data base, the master data base e.g. located by a telecommunication service provider. Therefore, the data or subsets of data of a master data base has to be provided to each one of a number of remote slave data bases, e.g. for providing fixed number portability changing between different service providers. To keep an actual data image of one subset of data in a slave data base, an instant data filter must be provided between the master data base and said slave data base.
Every time, if new data is entered into the master data base, e.g. if a new subscriber has to be entered or if subscriber data has to be updated, this data must be sent to the remote or slave data bases. The master data base, for administrative purposes, contains more data than necessary for the control of the telecommunications network. Moreover, the master data base contains possibly information about states, that are activated in the future. Therefore the master data base has different data structure than proxy- and slave data bases.
For de-coupling of the master data base from the slave data bases, a proxy data base at service providers side is connected between the master data base and the slave data bases. Updates of the master data base are loaded into the proxy data base(s). The proxy data base carries out the further forwarding of the updates to the slave data bases. The proxy data base contains exactly the same data (data mirror), that the slave data bases should contain after updating.
However, the synchronisation of the three data bases: master, proxy and slave data base is difficult. On the other hand, maintaining multiple physical data bases at service providers side is costly. Moreover, it is not possible to perform a consistent backup of multiple physical data bases.